Fried chicken in general has been around since long before KFC was founded and im sure plenty of african american women had their own recipes but the KFC recipe was his mamas (who was white) tho probably tweaked by the company cooks later on. Now theres always a posdibility his mama patterned her recipe from a black housekeeper or something. Who knows. It was WAY before KFC was even a concept thi.
It's quite plausible but highly unprovable,but it does make sense,after all he was a southern Colonel which implies a plantation owner which had slaves as workers cooking cleaning,but the time frame is not right.